The present invention is directed to an apparatus and method for treating contact lenses. More particularly, the invention is directed to a stand-alone apparatus and method by which contact lenses can be enzymatically cleaned without the need for abrasion or the need to perform the traditional steps of either inactivating the enzyme or thoroughly washing the residual enzyme from the lenses. In a particularly advantageous form, the apparatus is single-use and disposable, and comprises a housing including a pair of closable liquid sealed containers sized and shaped to accept and retain a lens therein such that the lens is brought into contiguous wetted contact with an enzyme enriched layer during the treatment process.
Contact lenses have come into wide use for correcting a wide range of vision deficiencies or cosmetic use. Typically, such lenses are formed from a thin transparent plastic material shaped and dimensioned to fit over the cornea of the eye. The lenses have an optical surface that includes a concave interior first optical surface for contact with the eye, an opposed and optically associated convex exterior second optical surface, and a surrounding edge. The two surfaces together define a lens that may be medically prescribed for a particular eye.
Depending on the polymer material used to construct the lenses, the lenses may be either "hard" or "soft". Hard contact lenses, which are comparatively more rigid, are typically formed from a relatively hydrophobic material such as polymethyl methacrylate (PMMA). Soft contact lenses, which are comparatively more pliant, are typically formed from a relatively hydrophilic polymer such as hydroxyethyl methacrylate (HEMA), which has the property of being able to absorb and bind a proportionately large amount of water within the polymer network. Soft contact lenses formed from such hydrophilic polymers, when hydrated, are more comfortable to wear than hard lenses because they better conform to the cornea of the eye and cause less irritation when worn for extended periods. For this reason, the great majority of contact lenses presently being prescribed are of the soft type.
Unfortunately, all contact lenses, and, in particular, soft lenses, while being worn collect contaminants from the eye and its environment. These contaminants, for example, may include proteins and lipids from the tear fluid of the eye, and foreign substances such as cosmetics, soaps, airborne chemicals, dust and other particulate matter. Unless periodically removed, these contaminants may cause abrasion to the surface of the eye, may impair the visual acuity of the lens, and may serve as a nutrient media for potentially harmful microorganisms.
Furthermore, with regard to soft contact lenses for wearing comfort it is necessary that they be maintained uniformly wetted at all times. While on the eye, the moisture content of the hydrophilic material of the lenses is maintained by tear fluid. However, when the lenses are removed for an extended period, as for cleaning or while sleeping, the lenses may dry out and become irreversibly damaged unless they are externally hydrated.
Consequently, various apparatus and methods have been developed for cleaning and hydrating contact lenses. For example, cleaning apparatus has been provided wherein the lenses are submersed in a variety of liquid cleaning agents, such as surfactants, oxidants, disinfectants, enzymatic cleaners, or abrasives. Other cleaning apparatus has been provided which included mechanically operated or electrically powered components for vibrating, rotating, abrading, scrubbing, heating, agitating, subjecting to ultrasonic energy, or otherwise mechanically manipulating the lenses to enhance the cleaning action of the cleaning agent.
Such prior apparatus and methods have not been entirely satisfactory for various reasons, including lack of cleaning effectiveness with respect to certain of the various contaminants found on the lenses, undesirable complexity, excessive time required for use, harshness to the lens material and dependence on an external power source.
Furthermore, certain prior lens cleaning apparatus and methods required added post-cleaning lens treatment procedures such as thorough rinsing before the lenses could be returned to the eye. For example, an important concern relating to the enzymatic cleaning systems currently being employed is the need to remove the enzymatic matter prior to placing the cleaned lens in the eye. Placing a lens contaminated with enzymatic matter into the eye may be potentially detrimental to the eye. Accordingly, users of enzymatic cleaners have been advised to thoroughly rinse the contact lens free of cleaning enzyme prior to placing the cleaned lens in the eye. This rinsing step, however, requires user compliance to be effective. Users may consider such rinsing unnecessary. Users also may not, and/or may not be able to, rinse the lens thoroughly enough to remove all residual enzymatic matter. As a result, active enzyme can come into contact with the eye. Additionally, in some instances, even thoroughly rinsing the lenses may not be totally effective in removing residual enzymatic matter bound to the lens.
U.S. Pat. No. 5,783,532 recognizes the problem of residual enzymatic matter on the lens and discloses an enzymatic cleaning composition containing a component which is asserted to be effective when released to deactivate the enzyme. This system, however, even if effective, still relies on the user to complete the steps necessary to deactivate the enzyme and to wait for complete inactivation to occur before placing the cleaned lens in the eye. Thus, in such a system, the problems associated with residual enzymatically active matter on the lens still exist if the lens is removed from the cleaning composition prior to complete inactivation. Additionally, even if inactivated, inactive enzymatic protein may still adhere to the lens and may cause an associated allergic reaction.
Therefore, a demand exists for an apparatus and method by which contaminated contact lenses can be conveniently and effectively enzymatically cleaned with minimum residual enzymatic matter remaining on the lens.
Accordingly, it is a general object of the present invention to provide a new and improved system, apparatus and method for cleaning contaminated contact lenses.
It is a more specific object of the invention to provide an apparatus for cleaning contaminated contact lenses wherein the lenses are enzymatically cleaned.
It is a further object of the present invention to provide a disposable single-use apparatus for enzymatically cleaning contaminated contact lenses having closable liquid-sealed container within which the lenses are contained while being cleaned.
It is a further object of the invention to provide a self contained apparatus for enzymatically cleaning a contaminated contact lenses wherein the optical surfaces of the lenses may be received in a wetted environment in contiguous contact with an enzyme enriched layer whereby contaminants from the lenses can be removed without the application of external force.
It is a further object of the invention to provide an apparatus and method of enzymatically cleaning contaminated contact lenses wherein the lenses can be removed from the cleaning environment at any time and placed in the eye with generally less risk of residual enzymatic matter remaining on the lens relative to that potentially present from conventional enzymatic treatment processes.